Inorganic arsenic is classified by the U.S. EPA as a known human carcinogen, based on extensive population studies of lung cancers following inhalation exposure, and skin cancers following ingestion of contaminated drinking water in adults; arsenic exposure also may be associated with a higher incidence of bladder, liver, kidney, and prostate cancer.

While both the 2012 and 2014 Consumer Reports concerned arsenic levels in US rice, no previous study has evaluated long-term consumption of total rice, white rice and brown rice in relation to risk of developing cancers.

We investigated this in the female Nurses’ Health Study (1984-2010), and Nurses’ Health Study II (1989-2009), and the male Health Professionals Follow-up Study (1986-2008), which included a total of 45,231 men and 160,408 women, free of cancer at baseline. Validated food frequency questionnaires were used to measure rice consumption at baseline and repeated almost every 4 years thereafter.

During up to 26 years of follow-up, we documented 31,655 incident cancer cases (10,833 in men and 20,822 in women).

Compared to participants with less than one serving per week, the multivariable RRs of overall cancer for individuals who ate at least 5 servings per week were 0.97 for total rice (95% CI: 0.85-1.07), 0.87 for white rice (95% CI: 0.75-1.01), and 1.17 for brown rice (95% CI: 0.90-1.26). Similar non-significant associations were observed for specific sites of cancers including prostate, breast, colon and rectum, melanoma, bladder, kidney, and lung. Additionally, the null associations were observed among European Americans and non-smokers, and were not modified by BMI.

Long-term consumption of total rice, white rice or brown rice was not associated with risk of developing cancer in US men and women.